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Programming via GPIB and VXI
4
Agilent VISA User’s Guide 107
Although the resource handles the allocation and operation of the
window, the programmer must free the window via
viUnMapAddress
when finished. This makes the window available for the system to
reallocate.
Sample: MEMACC Resource Program
This program demonstrates one way to use the MEMACC resource to
open the entire VXI A16 memory and then calculate an offset to address
a specific device.
/* peek16.c */
#include <stdio.h>
#include <stdlib.h>
#include <visa.h>
#define EXIT1
#define NO_EXIT 0
/* This function simplifies checking for VISA
errors. */
void checkError( ViSession vi, ViStatus status,
char
*errStr,int doexit){
char buf[256];
if (status >= VI_SUCCESS)
return;
buf[0] = 0;
viStatusDesc( vi, status, buf );
printf( "ERROR 0x%lx (%s)\n ’%s’\n", status,
errStr,
buf );
if ( doexit == EXIT )
exit ( 1 );
}
void main() {
ViSession drm;
ViSession vi;
ViUInt16inData16 = 0;
ViUInt16peekData16 = 0;
ViUInt8*addr;